Revision of Microtylopteryx Rehn 1905 (Orthoptera, Acrididae, Ommatolampinae)

Abstract

Rehn's (1955) two subgenera Microtylopteryx (Microtylopteryx) and Microtylopteryx (Tristanacris), each comprising several species and subspecies, are here each considered to represent a single species, M. hebardi Rehn 1905 and M. fusiformis Rehn 1905 respectively. I arrive at this conclusion on the basis of a) the genital anatomy, and b) morphometric analysis of all the previously named taxa and several previously unsampled populations. There are no differences within each of these taxa in internal or external genital structure. In the morphometric analysis, measures specifically designed to correspond to Rehn's diagnoses were used, and new material was collected from the various type localities to supplement the original material. The results show that the original diagnoses, which were based on small samples, do not adequately represent the populations from which the type series were drawn.Virtually every geographically circumscribed population which has been investigated differs from the rest, often significantly, in the average of one or more quantitative characters. However, the degree of overlap between the different populations in the range of these characters is typically very large, and often complete, and individual specimens therefore cannot be allocated reliably to particular populations on the basis of their morphology. All such overlapping populations are here considered to belong to a single taxon. Where, exceptionally, there is no overlap between populations in some character, and individuals can be reliably allocated to a specific population on its basis, subspecific ranks have been allocated.Within Microtylopteryx (Microtylopteryx), M. hebardi caligo Rehn is synonymized with M. hebardi Rehn, and M. nigrigena Hebard is relegated to subspecific rank as M. hebardi nigrigena. Within M. (Tristanacris) two species (talamancae Rehn, tristani Rehn) and one subspecies (fusiformis lamprus Rehn) are synonomized with M. fusiformis Rehn. M. worthi Rehn and M. chiapensis Rehn are relegated to subspecific rank within M. fusiformis, and one further new subspecies (M. f. fastigiata n. ssp) from Western Panama is erected. Each of Rehn's subgenera thus becomes monospecific, and it is suggested that the division into two subgenera is now redundant.A key to species and subspecies is given, and distribution maps.